but then there are civilian equivalents that are equally vague. Cross country gliding competitions spring to mind. They cover vast swathes of the countryside but in reality hardly constitute swarms of gliders from surface to infinity at all hours of the day.
The threatening "Strongly advised to avoid" has NEVER appeared in a civillian notam. Scheduled air sevices, oil industry traffic, flying schools, survey aircraft, and lift helicopters would have great loss of revenue if they did this, and would cause considerable disruption to the economy.
(As a pensioner, flying for pleasure, with time on my hands, I didn't fly in the good weather earlier this week, due to the assorted activities. For me it was no big deal to go walking instead. )